(1) Field of the Invention
The present invention relates to switching DC—DC converters, using CMOS switching transistors.
(2) Description of Prior Art
Actual switching DC—DC converters have disadvantages in specific operating regions due to different reasons for power losses. Large switching transistors with low RDSon provide favorable efficiency at high output currents, but need high currents to charge/discharge the switching transistor's gate, resulting in poor efficiency at low output currents. Small transistors are more efficient at low currents, but as a consequence they are poor at high currents.
FIG. 1 shows one conceptual circuit diagram of a buck converter out of a variety of possible implementations of DC—DC converters.
U.S. Pat. No. 6,462,962 (to Cuk) describes a circuit that implements a lossless switching DC-to-DC converter with lossless switching time control for up to four controllable switches, with each switch meeting the specific current-voltage switching characteristics.
U.S. Pat. No. 6,487,094 (to Weng, et al.) discloses a high efficiency DC—DC power converter, where the voltage across the main switch due to leakage inductance of the transformer is clamped and leakage energy of the transformer is recycled instead of being dissipated so as to improve operating efficiency.
U.S. Pat. No. 4,859,927 (to Meijer) shows a highly efficient switching regulator for a field effect transistor employed in a regulated power supply as the switching element for an unregulated power source, using a pair of complementary control transistors.